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Biomedical subjects

T Liu

Publications and source records attributed to T Liu.

At least 217 records · Page 12Linked to original sources
PubMed1999

Emergency medical care: types, trends, and factors related to nonurgent visits.

OBJECTIVES: To describe and compare national trends in ED use by statistical analyses on data from the 1992 to 1996 National Hospital Ambulatory Medical Care Survey (NHAMCS) with a special interest in factors related to nonurgent visits. METHODS: The NHAMCS collects data for ED visits using a four-stage national probability sample. Data from 135,723 ED visits in 1992-1996 were analyzed using the chi-square test for proportions with logistic regression modeling for multivariate analysis. RESULTS: More than half of the ED visits were considered nonurgent. There was a decreasing trend for nonurgent ED visits over the first three years of the sample (54.0% to 52.1%, p < 0.05). The proportion of ED visits for nonurgent care bounced back in 1995 (54.7%) and 1996 (54.1%). Significant variation existed in the proportion of nonurgent care visit based on disease category, age, race, and insurance coverage status. Marked variation in nonurgent visits also existed among geographic regions and types of hospital ownership. CONCLUSIONS: Analyses of data from the NHAMCS identify trends in ED use. The study of nonurgent ED visits with this database has inherent methodologic problems such as retrospective coding and geographic coding inconsistency. Since the nonurgent visit is clearly linked to certain social-demographic factors, addressing these underlying issues by establishing a comprehensive health care system is a priority.

Adult↗
PubMed1999

The transcriptional switch of bacteriophage WPhi, a P2-related but heteroimmune coliphage.

Phage WPhi is a member of the nonlambdoid P2 family of temperate phages. The DNA sequence of the whole early-control region and the int and attP region of phage WPhi has been determined. The phage integration site was located at 88.6 min of the Escherichia coli K-12 map, where a 47-nucleotide sequence was found to be identical in the host and phage genomes. The WPhi Int protein belongs to the Int family of site-specific recombinases, and it seems to have the same arm binding recognition sequence as P2 Int, but the core sequence differs. The transcriptional switch contains two face-to-face promoters, Pe and Pc, and two repressors, C and Cox, controlling Pe and Pc, respectively. The early Pe promoter was found to be much stronger than the Pc promoter. Furthermore, the Pe transcript was shown to interfere with Pc transcription. By site-directed mutagenesis, the binding site of the immunity repressor was located to two direct repeats spanning the Pe promoter. A point mutation in one or the other repeat does not affect repression by C, but when it is included in both, C has no effect on the Pe promoter. The Cox repressor efficiently blocks expression from the Pc promoter, but its DNA recognition sequence was not evident. Most members of the P2 family of phages are able to function as helpers for satellite phage P4, which lacks genes encoding structural proteins and packaging and lysis functions. In this work it is shown that P4 E, known to function as an antirepressor by binding to P2 C, also turns the transcriptional switch of WPhi from the lysogenic to the lytic mode. However, in contrast to P2 Cox, WPhi Cox is unable to activate the P4 Pll promoter.

Amino Acid Sequence↗
PubMed1999

Association of influenza virus matrix protein with ribonucleoproteins.

To characterize the sites and nature of binding of influenza A virus matrix protein (M1) to ribonucleoprotein (RNP), M1 of A/WSN/33 was altered by deletion or site-directed mutagenesis, expressed in vitro, and allowed to attach to RNP under a variety of conditions. Approximately 70% of the wild-type (Wt) M1 bound to RNP at pH 7.0, but less than 5% of M1 associated with RNP at pH 5.0. Increasing the concentration of NaCl reduced M1 binding, but even at a high salt concentration (0.6 M NaCl), approximately 20% of the input M1 was capable of binding to RNP. Mutations altering potential M1 RNA-binding regions (basic amino acids 101RKLKR105 and the zinc finger motif at amino acids 148 to 162) had varied effect: mutations of amino acids 101 to 105 reduced RNP binding compared to the Wt M1, but mutations of zinc finger motif did not. Treatment of RNP with RNase reduced M1 binding by approximately half, but even M1 mutants lacking RNA-binding regions had residual binding to RNase-treated RNP provided that the N-terminal 76 amino acids of M1 (containing two hydrophobic domains) were intact. Addition of detergent to the reaction mixture further reduced binding related to the N-terminal 76 amino acids and showed the greatest effect for mutations affecting the RNA-binding regions of basic amino acids. The data suggest that M1 interacts with both the RNA and protein components of RNP in assembly and disassembly of influenza A viruses.

Animals↗
PubMed1999

Immunopotentiating activity of nigerooligosaccharides for the T helper 1-like immune response in mice.

The immunopotentiating activity of nigerooligosaccharides (NOS), a mixture of nigerose, nigerosyl glucose and nigerosyl maltose, was studied in vitro and in vivo in mice. Mitogen-induced proliferation of splenocytes from normal mice was augmented in a dose-dependent manner by nigerose of NOS. NOS enhanced interleukin 12 (IL-12) and interferon-gamma (IFN-gamma) production by normal splenocytes in the presence of the potent IL-12 inducer, heat-killed Lactobacillus plantarum L-137, in vitro. Consistent with the in vitro finding, L. plantarum L-137-induced IL-12 production and IL-2-induced IFN-gamma production were augmented in mice fed with a 14.6% NOS diet for 2 weeks compared with mice fed with a control diet. Notably, mice fed with the NOS diet showed significantly longer survival time than the control mice after the induction of an endogenous infection by administering 5-fluorouracil in a lethal dose. Taken together, these results suggest that NOS may exert immunopotentiating activity through the activation of an IL-12-dependent T helper 1-like immune response.

Animals↗
PubMed1999

Reduced in vitro production of interferon-gamma, interleukin-4 and interleukin-12 and increased production of interleukin-6, interleukin-10 and tumour necrosis factor-alpha in systemic lupus erythematosus. Weak correlations of cytokine production with disease activity.

Production of cytokines in unstimulated and mitogen-stimulated cultures were evaluated by ELISPOT in 34 SLE patients with low to moderate disease activity and 23 healthy controls. Significantly reduced production of IFN gamma, IL4 and IL12 and significantly increased production of IL6, IL10 and TNF alpha were found in patients with SLE. Regression analysis revealed that production of all six cytokines tended to decrease with increasing disease activity, but negative correlation with SLEDAI was significant (p < 0.05) only for PHA-stimulated IL4, unstimulated and PHA-stimulated IL10 and SAC-stimulated IL6. Negative correlation of stimulated and unstimulated IL6 and TNF alpha production with anti-DNA antibody levels were also significant.

Adolescent↗
PubMed1999

Interlaboratory comparison of ultrasonic backscatter, attenuation, and speed measurements.

In a study involving 10 different sites, independent results of measurements of ultrasonic properties on equivalent tissue-mimicking samples are reported and compared. The properties measured were propagation speed, attenuation coefficients, and backscatter coefficients. Reasonably good agreement exists for attenuation coefficients, but less satisfactory results were found for propagation speeds. As anticipated, agreement was not impressive in the case of backscatter coefficients. Results for four sites agreed rather well in both absolute values and frequency dependence, and results from other sites were lower by as much as an order of magnitude. The study is valuable for laboratories doing quantitative studies.

1-Propanol↗
PubMed1999

[Identification of mutations of SRD5A2 gene and SRY gene in patients with hypospadias].

OBJECTIVE: To identify possible molecular mechanism underlined hypospadias and any relationship of the mutations of SRD5A2 gene and SRY gene to hypospadias. METHODS: Twenty-three blood samples from the patients with hypospadias were obtained from Aug.1996 to Jan. 1998. DNA was extracted from blood leukocytes. Exons 1 to 5 of the SRD5A2 gene and exon of the SRY gene were amplified by PCR. Mutation detection was performed using PCR-SSCP/silver staining and direct DNA sequencing. RESULTS: In 3 cases (named 5R2-China-1, 5R2-China-2, and 5R2-China-3), DNA sequencing revealed that a homozygous change from nucleotide G to A occurred in 5R2-China-1 and 2, leading to a substitution of glutamine to arginine in the codon 227(Arg 227 to Gln). In the third patient (5R2-China-3), DNA sequencing revealed two different heterozygous mutations(Arg 227 to Gln, Phe 186 to Leu) in exon 4 of the SRD5A2 gene. No mutation of SRY gene was found in all patients. CONCLUSION: The mutation of SRD5A2 gene affects the differentiation of the external genitalia and may play a role in the etiology of hypospadias. Since no mutation of SRY gene was found, this study might suggest that the mutation of SRY gene is not an important event in hypospadias. Codon 227 is a hotspot site of mutation within the gene. The mutation of codon 186(Phe 186Leu) represents a new form of SRD5A2 mutation.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1999

Evaluation of recombinant chitinase antigen in serological diagnosis and surveillance of lymphatic filariasis.

Apply recombinant chitinase fusion protein antigen, enzyme-linked immunosorbent assays examined anti-filarial antibodies and evaluated of useful value in serological diagnosis and surveillance of lymphatic filariasis. The test jirds were immunized and infected by chitinase and B. malayi third stage larvae respectively. Functional protein molecular of chitinase was analyzed by SDS-PAGE, Western blot. The result shown that jirds from microfilaremia (mf) and donors with Mf were directly to react with chitinase antigen that positive rate was 100%, but Mf-xt antigen was only 80%. Normal jirds and persons sera from unepidemic control donors all were negative. False positives of 5% and 20% reacted with chitinase and Mf-xt antigens respectively. The results indicate that recombinant chitinase antigen is suitable for detection of active occult or patent lymphatic filariasis with daytime blood samples in residents of endemic areas, is easy to be performed and inexpensive.

Animals↗
PubMed1999

Progress in Two-Dimensional and Three-Dimensional Ultrasonic Tissue-Type Imaging of the Prostate Based on Spectrum Analysis and Nonlinear Classifiers.

Spectrum analysis of radiofrequency (RF) ultrasonic echo signals often can sense tissue differences that are not visible on conventional ultrasonic images. Spectrum-analysis parameter values combined with other variables, such as serum prostate specific antigen (PSA) concentration, can be classified by neural networks to distinguish effectively between cancerous and noncancerous prostate tissues. Images based on neural network classification of spectral parameters and clinical variables can be advantageous for biopsy guidance, staging, and treatment planning and monitoring. A study based on 644 biopsies from 137 patients showed that these methods are significantly superior to B-mode image interpretation for differentiating cancerous from noncancerous prostate tissues. Using the histologic determination of tissue types as the gold standard, the area under the receiver-operator characteristic (ROC) curve for neural network classification based on spectrum analysis and PSA value for the 644 biopsies was 0.87 +/- 0.04, and the ROC curve are for a level-of-suspicion (LOS) assignment based on B-mode imaging was 0.64 +/- 0.04. Color-encoded and gray-scale images derived from neural network assignment of suspicion for cancer at each pixel location showed remarkable detail and suggested potential clinical value for biopsy guidance using real-time two-dimensional (2D) images and staging, treatment planning, and monitoring using three-dimensional (3D) images.

Journal Article↗
PubMed1999

[The clinical significance of preserving superior epigastric vessels in Cohen incision].

OBJECTIVE: To study the clinical significance of preserving epigastric vessels in Cohen incision. METHODS: 42 cases of pregnant women were performed cesarean section using Cohen incision. One side vessel of incision was preserved, the other side was cut off. By self control comparison, skin temperature of two sides incision has been taken by CET (computer electric infrared thermograph) on the third day post operation. The thinkness of scar was measured with vernier calipers on the 40th day post operation. RESULTS: The skin temperature difference between both sides of incision was (0.098 +/- 0.088) degree C. On the cut side the skin temperature was higher than that of the other side (P < 0.01). The scar thickness of cut side was (3.61 +/- 0.61) mm, the other side was (3.10 +/- 0.68) mm. The difference was significant (P < 0.01). CONCLUSION: The inflammatory reaction and formation of scar can be decreased by means of preserving superior epigastric vessels in Cohen incision.

Cesarean Section↗
PubMed1999

[The diagnostic value of computed tomography and ultrasonography for detecting hypoxic-ischemic encephalopathy].

OBJECTIVE: To investigate diagnostic value of computed tomography (CT) and ultrasonography for detecting hypoxic-ischemic encephalopathy (HIE) and to evaluate their clinical implications. METHODS: 94 neonates were examined with CT and ultrasonography, respectively, for detecting HIE and the results were compared to clinical investigation. RESULTS: Significant difference (P < 0.01) was found for diagnosis of mild and moderate HIE by CT and ultrasonography. Compared with clinical diagnosis, the agreement rates of ultrasonography and CT were 83% and 39% (P < 0.01) for mild HIE, and 100% and 43% (P < 0.01) for moderate HIE respectively. There was no difference for detecting severe HIE among clinical diagnosis, CT and ultrasonography. Additionally, 9 cases with intracranial hemorrhage were detected by CT in which only 3 cases were found by ultrasonography. CONCLUSIONS: Compared with clinical finding for diagnosis of mild and moderate HIE, the agreement rate of ultrasonography is higher than that of CT. However, CT is more sensitive to detect intracranial hemorrhage than ultrasonography.

Female↗
PubMed1999

[Effects of protocol HX-97 on mobilization, collection and hematopoietic reconstitution of peripheral blood stem cells transplantation].

In order to enhance the effects of peripheral blood stem cell mobilization, collection and hematopoietic reconstitution, we observed and evaluated the effects of Protocol HX-97 on 22 patients who received allogeneic or autologous peripheral blood stem cell transplants from April 1997 to June 1999. rhG-CSF was used for mobilization at a dose of 300 micrograms/day for 6 days; the sixth dose was given an hour and a half before leukapheresis. High dose chemotherapy and rhG-CSF were given for autologous peripheral blood stem cell mobilization; the chemotherapy should be intensive enough to reduce the patients' peripheral WBC to less than 1.0 x 10(9)/L, and the beginning of using rhG-CSF should be just at the time of WBC's rising from the nadir. rhGM-CSF and rhG-CSF were given sequentially for hematopoietic reconstitution after transplantation. The results showed that leukaphereses were successfully performed for peripheral blood stem cell collection. Sixteen cases needed apheresis only once, and 6 cases needed it twice. The harvests were 2.5-10.7 x 10(8)/kg MNC, 2.5-20.0 x 10(6)/kg CD34+ cells (including 1.8-7.5 x 10(6)/kg CD34+CD33-, 0.7-12.5 x 10(6)/kg CD34+CD33+), and 3.5-6.3 x 10(5)/kg CFU-GM. Hematopoietic function recovered to > 0.5 x 10(9)/L of neutrophil count in allo-PBSCT at 14-20 days and in auto-PBSCT at 12-20 days, and to > 20 x 10(9)/L of platelet count in allo-PBSCT and in auto-PBSCT at 16-34 days and 16-28 days, respectively. At day +30 post-transplantation, chromosome analysis and DNA finger print assessment of bone marrow cells indicated that the patients' hematopoietic function had been reconstituted. This study suggests that Protocol HX-97 is an effective approach to mobilization of peripheral blood stem cell transplantation, and it is relatively cost-effective.

Adult↗
PubMed1999

[Video-assisted thoracic surgery in the management of chest diseases].

OBJECTIVE: To summarize short-term results of video-assisted thoracic surgery for 322 patients with chest diseases in Beijing from October 1992 to October 1998 and discuss the role of thoracoscopy in the diagnosis and therapy of thoracic diseases in China. METHODS: Three hundred and twenty-two patients (273 men and 85 women) underwent video-assisted thoracic surgery for spontaneous pneumothorax (113), lung cancer (83), solitary pulmonary nodules (52), pleural diseases (19), mediastinal tumors (11), myasthenia gravis (5), thoracic trauma (10), esophageal cancer (7), benign esophageal diseases (11), and other indications (11). Data on thoracoscopic procedures, morbidity and mortality, conversion to open procedures were collected for all patients. RESULTS: Three hundred and thirty-nine thoracoscopic procedures were performed in 322 patients. These procedures included blebectomy and pleurodesis (121), wedge resections of pulmonary nodules (57), lobectomy and pneumonectomy (48), pleural biopsies and pleurodesis (52), excision of mediastinal mass (11), thymectomy (5), esophagectomy (6), and other procedures (39). Conversion to thoracotomy was required in 9 patients (0.28%). The overall incidence of postoperative complications was 7.5% (24/322). Two patients died postoperatively. CONCLUSIONS: Video-assisted thoracic surgery is a safe and effective technique in selected patients with chest diseases. The results in this group were similar to those reported previously in North American.

Adolescent↗
PubMed1999

[Specific activity of the promoter containing Myc-Max response elements in c-myc-overexpressing cells].

OBJECTIVE: To investigate the specific activity of a hybrid promoter which is constructed by replacing the third domain of herpes simplex virus (HSV) thymidine kinase (TK) promoter with the Myc-Max response elements. METHODS: Myc-Max response elements were ligated with a third domain-deleted HSV-TK promoter by cloning and subcloning PCR products. Then a luciferase-expressing plasmid, in which the luciferase gene was put under the control of hybrid promoter, was constructed and transfected transiently into the cell lines which had been demonstrated to be c-myc over- or low-expressing by Northern blot hybridization. The luciferase activities in these cells were detected. RESULTS: In c-myc over-expressing cells, the hybrid promoter (Mpr) led to high levels of (81,966 +/- 43,238) relative light units (RLUs) in PC-2 cells and (70,563 +/- 22,435) RLUs in PC-7 cells, which were 78- and 150-fold higher than those coming from the third domain-deleted TK promoter (Epr), and also 6.9- and 1.7-fold higher than the activities controlled by TK promoter. However, Mpr showed a very low activity in c-myc low-expressing cells, in which the luciferase activity was (431 +/- 73) RLUs, similar to (601 +/- 141) RLUs produced by Epr. CONCLUSION: The activity of hybrid promoter, which is composed of Myc-Max response elements and the third domain-deleted TK promoter, possesses cell-type specificity for c-myc-overexpressing cells.

Animals↗
PubMed1999

[A study on the conjugation of Streptococcus mutans adhesins and its salivary receptors].

OBJECTIVE: To investigate the conjugation specificity of Streptococcus mutans' adhesins and their salivary receptors. METHODS: Include purified salivary receptor or adhesin competitive bacteria adhesion inhibition test and enzyme linked immuno-receptor assay (ELIRA) on S. mutans WD9463A. RESULTS: Salivary amylases can both enhance and competitively inhibit the adhesion of the strain to HA, while IgA degraded fragments and MW = 13,000 protein only promote its adhesion. P1 and a 117,000 surface protein of WD9463A both inhibit adhesion of the strain to IgA degraded fragments and salivary amylases. An 127,000 protein of WD9463A and a kind of GTFase inhibit its adhesion to IgA degraded fragments and salivary amylases respectively. No conjugation was found between IgA degraded fragments and the adhesins, while reaction between amylases and the adhesins had basically accordance with adhesion inhibition test. CONCLUSION: The adhesion of S. mutans is a result of reaction between multireceptors and multiadhesins.

Adhesins, Bacterial↗
PubMed1999

[The effect of gancao on glucocorticoid receptors in chronic obstructive pulmonary disease].

OBJECTIVE: To study the effect of gancao and glucocorticoid on glucocorticoid receptors. METHODS: The number of GCR of peripheral blood leukocytes was determined and FEV1% was assessed in 45 COPD patients and 10 control subjects. RESULTS: GCR was significantly lower in COPD patients during acute attack than in control subjects while F and ACTH were significantly higher (P < 0.001). In gancao, glucocorticoid and combination of gancao and glucocorticoid treated groups FEV1% was higher after treatment, especially in the combination group(P < 0.001). Gancao induced up-regulation of GCR while glucocorticoid induced down-regulation of GCR, but combination of gancao and glucocorticoid had no effect on GCR. CONCLUSIONS: Gancao might reverse the down-regulation of glucocorticoid on GCR, thus enhance and prolong the effects of glucocorticoids.

Adrenocorticotropic Hormone↗
PubMed1999

[Effect of nourishing kidney to inducing resuscitation method on psychic evaluation table in patients of vascular dementia].

OBJECTIVE: To probe the effect of the nourishing Kidney to inducing resuscitation (NKIR) on psychic evaluation table in patients of vascular dementia. METHODS: Modified Sanjiasan Granule (MSG), a representative recipe of NKIR, was used to treat 26 patients with vascular dementia, 7 g per day orally for one month as one therapeutic course, and the effect of treatment was evaluated by psychic evaluation table. RESULTS: MSG could increase the total scoring of Hagayakawa Dementia Scale and mini mental state examination (MMSE) as well as the single entry scoring of MMSE. It could reverse the process of vascular dementia in psychic evaluation table. CONCLUSION: MSG has good effect in improving intelligence and anti-dementia.

Aged↗